In this work, we investigate the processes leading to the room-temperature growth of silicon carbide thin films by supersonic molecular beam epitaxy technique. We present experimental data showing that the collision of fullerene on a silicon surface induces strong chemical-physical perturbations and, for sufficient velocity, disruption of molecular bonds, and cage breaking with formation of nanostructures with different stoichiometric character. We show that in these out-ofequilibrium conditions, it is necessary to go beyond the standard implementations of density functional theory, as ab initio methods based on the Born-Oppenheimer approximation fail to capture the excited-state dynamics. In particular, we analyse the Si-C60 collision within the non-adiabatic nuclear dynamics framework, where stochastic hops occur between adiabatic surfaces calculated with time-dependent density functional theory. This theoretical description of the C60 impact on the Si surface is in good agreement with our experimental findings.

Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature

Taioli, Simone;Dapor, Maurizio;
2013-01-01

Abstract

In this work, we investigate the processes leading to the room-temperature growth of silicon carbide thin films by supersonic molecular beam epitaxy technique. We present experimental data showing that the collision of fullerene on a silicon surface induces strong chemical-physical perturbations and, for sufficient velocity, disruption of molecular bonds, and cage breaking with formation of nanostructures with different stoichiometric character. We show that in these out-ofequilibrium conditions, it is necessary to go beyond the standard implementations of density functional theory, as ab initio methods based on the Born-Oppenheimer approximation fail to capture the excited-state dynamics. In particular, we analyse the Si-C60 collision within the non-adiabatic nuclear dynamics framework, where stochastic hops occur between adiabatic surfaces calculated with time-dependent density functional theory. This theoretical description of the C60 impact on the Si surface is in good agreement with our experimental findings.
2013
Taioli, Simone; Giovanni, Garberoglio; Stefano, Simonucci; Silvio a., Beccara; Lucrezia, Aversa; Marco, Nardi; Roberto, Verucchi; Salvatore, Iannotta;...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/33150
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